Method of packaging friable bales of elastomeric material

ABSTRACT

Friable bales of elastomeric crumb formed of porous crumb having a bulk density within the range of 16 to 30 pounds per cubic foot and compressed into bales having a bulk density within the range of 24 to 45 pounds per cubic foot and packaged in separated loadfree compartments for storage or shipment without loss of friability.

United States Patent [1 1 Prescott et al.

[ Dec. 4, 1973 METHOD OF PACKAGING FRIABLE BALES OF ELASTOMERIC MATERIAL[75] Inventors: E. Elsworth Prescott; Edward F.

Copus, both of Baton Rouge, La.

[73] Assignee: Copolymer Rubber & Chemical Corporation, Baton Rouge, La.

[22] Filed: July 9, 1971 [21] Appl. No.: 161,161

[52] US. Cl 53/24, 206/46, 206/65 [51] Int. Cl B651) 63/02 [58] Field ofSearch 53/24 [56] References Cited UNITED STATES PATENTS 3,461,6418/1969 Zubik et a1. 53/24 2,779,974 2/1957 Billing et al 53/24 X3,477,562 11/1969 Allen et al. 53/24 X 3,529,540 9/1970 Ferris .1 53/24X Primary Examiner-Travis S. McG-ehee Att0rneyMcDougall, Hersh & Scott[57] ABSTRACT Friable bales of elastomeric crumb formed of porous crumbhaving a bulk density within the range of 16 to 30 pounds per cubic footand compressed into bales having a bulk density within the range of 24to 45 pounds per cubic foot and packaged in separated load-freecompartments for storage or shipment without loss of friability.

3 Claims, 5 Drawing Figures METHOD OF PACKAGING FRIABLE BALES OFELASTOMERIC MATERIAL This invention relates to elastomeric materials andmore particularly to elastomeric materials packaged in bales for supplyby the manufacturer of the elastomeric material to the users thereof. v

In the manufacture of snythetic elastomers, such as SBR rubber, EPDMrubbers, cyclopentadiene rubbers, chloroprene rubbers, butylene rubbers,butadiene homopolyrner and copolymer rubbers and the like, theelastomeric material is produced in the form of crumb which, afterdrying, is compressed into bales for shipment to compounders for use inthe manufacture of elastomeric products, such as belts, tires, mattingand the like. The bales are broken down by the compounders forformulating the desired amount of elastomeric material with otherrubbers, additives, fillers, curing or vulcanizing agents and the likein the manufacture of elastomeric products.

As in the preparation of EPDM elastomers, as representative ofelastomeric materials, the crumb is delivered by the dryer at anelevated temperature and fed to a baler for compaction underpressure toform a bale of the desired density and shape. The bales are delivered,as they are formed, to the packager which encloses the bales in awrapper of a moisture-proof film of plastic materialand then the balesare stacked in a carton for transfer to storage or shipment.

It has been foundthat the bales of elastomeric crumb are subject tofurther compaction at the time thatthey are stacked in the carton withthe result that the density of the bale, as measured .by specificgravity, continues to rise and the adhesion between the crumb isincreased to the extend that theultimate user experiences considerabledifficulty in breaking down the bale for removal of the desired amountof elastomeric material in the compounding operation and considerablymore work is required to effect the desired uniform distribution of theelastomeric material with the other in,-

gredients duringcompounding.

In addition, .a dense elastomeric crumb is provided which resistsadmixture for uniform distribution with the other ingredients inzthecompounding operation, with the result that a non-uniform and inferiorproduct is often produced.

Thus, it is an object of this invention to produce and to provide amethod for producing a friable bale of vention FIG. Us a perspectiveview of the rubber crumb, as delivered from the dryer;

FIG. 2 is a schematic view of thebaler for adhering the crumb into afriable bale;

FIG. 3 is aperspective view of the package formed of the bale wrapped inthe waterproof plastic;

FIG. 4 is an elevational view of the means in which the bales arestacked in a carton. for storage or.ship ment; and

FIG. 5 is a top plan view of the carton partially filled with balesstacked in accordance with the practice of this invention.

One of the important concepts of this invention re sides in theproduction of a low density crumb 10 of elastomeric material and thecompaction of the crumb to form a friable bale 12 which can be easilybroken down into segments for compounding and which is more easilycombined with others of the ingredients to produce the compounded rubberor elastomer.

Another of the important concepts of this invention is to provide meansfor packaging the friable bales of elastomeric material in a mannerwhereby the friability of the bale can be maintained over extendedperiods of time in storage or shipment without deterioration of thefriability of the bale or the ease by which the elastomeric material canbe blended or otherwise mixed with other ingredients to produce acompound in which the materials are more uniformly distributed to yieldan improved process and product.

Up .to the point that the elastomeric crumb is .dewatered and dried, theprocedure for the production ,of crumb of elastomeric material followsthat of conventional practice, such as described in US. Pat. Nos.3,055,856, 3,079,360 and 3,092,063, and the copending applicationSer.No. 795,664, filed Jan. 31, 1969, now US. Pat. No. 3,593,655, andentitled Meansrfor Extracting Water from Elastomeriic Materials.

Inthe foregoing application, description is made of theme of a modifiedFrench oil mill-for the extraction ofwater from the crumb and theissuance of the crumb as dry particles which are then advancedto thebaler for compaction to form the bale. The crumb that is produced by themodified French oil mill would normally have a density considerably inexcess of 30 to 3.5 pounds per cubic foot and the bale that is producedtherefrom would have a densitLin excess of 45 19 50 pound sfper cubicfoot before stacking for storage. or

crumb in forming the bale by an amount to increase the bulk density inthe bale byabout 50 percent or, in other words, to provide a bale ofthelower density crumb in whichthe bale has a bulkdensity withintherange of 24 to 45 pounds per cubic foot and preferably a bulkdensity ofabout 34 4 poundsper cubic foot.

EPDM crumb (EPsyn 5508 of Copolymer Rubber & Chemical CorporatiomBatonRouge, Louisiana) having a bulk density of 22. pounds per cubic foot,representative of a highly porous dry and friable crumb .10, can beproduced by processingthe wet crumbthrough a V. D. Anderson dryerwherein the final substantially dried crumb issues from the dryer toproduce ahighly porous crumb 10 having a bulkdensity of about 22 poundsper cubic foot and a temperature of about I50-I60 F.

For baling, the temperature of the EPDM crumb should not exceedl F. Itis desirable, however, to

allow the crumb to cool to a temperature less than F. and morepreferably to a temperature that is proportional to the ethylenecontent, if it issues from the dryer at a higher temperature.

It is desirable to minimize the amount of dwell of the ram with respectto the compressed bale, otherwise additional undesirable compaction willoccur. As a result, the amount of dwell should not be allowed to exceedto seconds and it is desirable to maintain the dwell to as near zero aspossible.

Even though the bale has the desired friability from the standpoint ofporosity and density when it is removed from the baler 20, if, as acontinuous operation, it is packaged by stacking in suitable shippingcartons, in accordance with the conventional practice heretoforeemployed, the bale will compact further by as much as 50 percent,especially those bales which are at the bottom of the stack and whichare subjected to the greatest static load of the bales superposedthereon. Thus much of the original advantage of controlled porosity anddensity is dissipated whereby many of the original problems return.

The following examples will set forth the conditions for the productionof a friable bale of EPDM rubber, but it will be understood that theactual operating conditions can be expanded, as will hereinafter be setforth, for the same or others of the synthetic elastomeric materials,such as of the type heretofore described, which are produced in the formof crumb and baled for packaging for storage or shipment to distantstations.

EXAMPLE 1 The baler was operated at 97 F. Approximately 2.45 cubic feetof low density EPDM crumb 10 having a bound ethylene content of 79percent was introduced into the cavity 22 having a width of 14 inchesand a length of 28 inches. The ram 24 was operated at 500 psi. for 8seconds to compress the crumb into a space having a height of 7 inchesafter which the ram was substantially immediately withdrawn to releasethe pressure with a dwell time of less than one second to produce a bale26 weighing 54 pounds having the dimensions of 7 X 14 X 28, inchescorresponding to a bulk density of about 34 pounds per cubic foot. A

This compares to a weight of 75 pounds for a nonfriable bale of smallsize produced of crumb of the type heretofore manufactured and providedfrom the modified French oil mill.

EXAMPLE 2 Similar conditions were used as stated in Example 1 exceptEPDM crumb having an ethylene content of 83 percent was used. Also, thespace height was controlled to 6"/einches and the baler was operated atl 10 F.

EXAMPLE 3 Similar conditions were used as stated in Example 2 andExample 1 except EPDM crumb having an ethylene content of 85 percent wasused. The baler was operated at 120 F.

EXAMPLE 4 Packaging Procedure The bale is delivered as a continuousoperation from the baler and wrapped for packaging in a heat-scalablemoisture-proof film of plastic material.

In accordance with the practice of this invention use is made of acarton 40, such as a carton formed of cardboard or corrugated cardboarddimensioned to have a width corresponding to or slightly greater than amultiple of the width of the bale, a length corresponding to or slightlygreater than a multiple of the length of the bale, and a heightcorresponding to a multiple of the height of the bale.

A partitioning member in the form of an insert 42 of egg crateconfiguration is inserted into the bottom of a carton to subdivide thelower portion into compartments 44 dimensioned to have a length andwidth corresponding to and preferably slightly greater than thecorresponding dimensions of the bale and a height corresponding to theheight of the bale. The insert may be formed with the outer walls of theoutermost compartments completely absent since reliance may be had uponthe walls 46 of the carton to define the outer walls of the outermostcompartments. The freshly formed bales are loaded into the compartmentswith a separate bale for each compartment.

When all of the compartments in the lower layer have been filled, acover sheet 48 in the form of a flat panel of cardboard, corrugatedcardboard or the like is positioned over the insert whereby the coversheet is supported substantially throughout its entire area on the upperedges of the insert, as distinguished from resting on the bales. Thecover sheet 48 can be formed with downwardly extending flanged edgeportions to embrace the underlying insert for greater stability.

When the cover sheet has been placed in position of use, a second insert50 of the same characteristics as the first is placed on top to define asecond layer of compartments which are adapted to be filled withseparate bales and this procedure is continued until the desired numberof layers is provided to fill the carton with each bale separatelyconfined in each compartment and resting solely on the separating coversheet between the layers so as to take any load off of the underlyingbales.

When the carton has been filled, a cover sheet can be applied over thetop layer or use can be merely made of the enclosure 52 to confine thebales within the carton. The enclosure may be in the form of flaps ofcardboard which are folded over to enclose the carton or use can be madeof a carton cover 52 which telescopes over the top of the carton and issecured thereto by adhesives, tapes or other binding.

It will be understood that the size and weight of the bales may varywithin the density range heretofore described and that correspondingvariations will follow with respect to the dimensional characteristicsof the compartments defined by the various inserts and separators in thecarton.

The invention is also applicable in the manner described to rubbers ofdifferent compositions which are fabricated in the form of packagesformed of compressed crumb particles.

It will be understood that other changes may occur with respect to theconstruction and composition of the bales of elastomeric material andthe carton in which they are packaged without departing from the spiritof the invention, especially as defined in the following claims.

We claim:

1. The method for producing a friable bale of elastomeric material fromEPDM crumb comprising the steps of providing a porous elastomeric crumbhaving a bulk density within the range of 16 to 30 pounds per cubicfoot, introducing the crumb into a mold cavity at a temperature below140F to about 97F, with the temperature proportional to the boundethylene content of theand enclosing the bale within a wrapper of awaterproof material.

2. The method as claimed in claim 1 in which the compression of thecrumb to form the bale is relieved with minimum dwell after the bale hasbeen reduced to the desired density.

3. The method as claimed in claim 1 in which the bale is formed when thedensity of the crumb is increased by about 50 percent.

* II I!

1. The method for producing a friable bale of elastomeric material fromEPDM crumb comprising the steps of providing a porous elastomeric crumbhaving a bulk density within the range of 16 to 30 pounds per cubicfoot, introducing the crumb into a mold cavity at a temperature below140*F to about 97*F, with the temperature proportional to the boundethylene content of the EPDM crumb with the bound ethylene content ofthe EPDM crumb being above about 79 percent, compressing the crumb by anamount to increase the bulk density to within the range of 24 to 45pounds per cubic foot to form a bale, removing the bale from the pressand enclosing the bale within a wrapper of a waterproof material.
 2. Themethod as claimed in claim 1 in which the compression of the crumb toform the bale is relieved with minimum dwell after the bale has beenreduced to the desired density.
 3. The method as claimed in claim 1 inwhich the bale is formed when the density of the crumb is increased byabout 50 percent.